This invention relates to an insert utilized to explosively expand a tube into engagement with the tube sheet and a method for holding the insert in a vertically oriented tube.
Mechanical expansion of tubes and tube sheets or rolling is well known in the art, a more recent development in explosive expansion of tubes into engagement with a tube sheet as described in U.S. Pat. Nos. 3,411,198 and 3,426,681. Explosive expanding is generally faster and more efficient than mechanically expanding and explosive expanding is accompanied by very little axial growth of the tube compared to mechanical expanding. Explosive expanding also requires less access to the tube sheet and reduces the amount of time personnel are in the proximity of the tube sheet. This latter advantage is particularly important when the heat exchanger is radioactive.